1. Field of the Invention
The present invention relates to a microscopic system for an examination of a crystal cleavage plane in semiconductor wafers, etc.
2. Description of the Prior Art
Recently, when producing a semiconductor device, various defects in products have been caused by crystal defects in the interior of silicon wafers. Specifically, it is known that the crystal defects in silicon wafers have a great influence on the yield in the diffusion process. Such crystal defects can be eliminated by controlling the initial oxygen concentration and the oxygen deposition in silicon. As a method for examining the crystal defects, the observation of a crystal cleavage plane in silicon wafers is considered to be important. For the examination of the crystal cleavage plane, an optical microscope is used. In a conventional method, a specimen was positioned by handwork using forceps or plastic clay so that a cleavage plane of the specimen becomes perpendicular to the optical axis of a microscope.
In the conventional method, every time the specimen was moved or focused on while using the microscope, the specimen needed to be repositioned by hand so that a cleavage plane of the specimen was perpendicular to the optical axis of the microscope. Disadvantageously it took much time (3-5 hours) and labor to do so. In addition, since it was difficult to hold the specimen so that the cleavage plane was precisely perpendicular to the optical axis of the microscope, the examination was not likely to be precise.